Before he was slain, Isildur became king of Arnor and Gondor. While he had been High King of both realms, he committed the rule of Gondor to his nephew Meneldil[3] who would become King of Gondor. With the death of his father and brothers, Valandil became heir to the throne of Arnor. However, since Valandil was only 13 years old, he would wait until he was 21 to become the king (in T.A.10).[1]

He ruled longer than any other king in the North or South kingdoms - 239 years. When he died in 249, he was succeeded by his son, Eldacar.[2]